Cichlid... IMO that you shouldn't be able to over-filter a tank. All you will be doing is removing more and more of suspended particulates but won't be affecting the bacterial populations. How long has this tank been set up?I suspect that you've an out-of-balance tank in which one of the basic components of the cycle isn't progressing to the next level giving you a bacterial bloom. Ammonia, Nitrite and Nitrates reading would be helpful in diagnosing your problem. When you clean your filters do you clean all of them at the same time? If you do, I'd alter that routine and leave one up and running until your next scheduled maintenance. Cleaning all your filters at the same time could remove most of the beneficial bacteria that works in part to keep your tank water clear!But finally, patience is pretty much all you need to practice in that your tank will eventually clear up. Note! Pet shops might try to sell you some clearing products but I would shy away from them. Bill

No such thing as too much filtration. Having several filters could possibly cause too much flow and turbulence for certain livestock. If your fish require calm water then its possible to have too many filters running.

Impossible to over oxygenate the average tank with just water movement and airstones. You would need to add hydrogen peroxide to over oxygenate the tank water.